Here is who should be first in line this fall when the H1N1 vaccine becomes available, the U.S. Centers for Disease Control announced today: Pregnant women, all children (except those under six months old), teens and young adults up to 24 years old, people with babies under six months old, health care workers and nonelderly adults who have underlying medical conditions.

“We really should go out full force to make sure these groups get addressed,” Anne Schuchat, the CDC National Center for Immunization and Respiratory Disease director, said at a press conference in Atlanta, Ga.

The entire group, estimated to sum up to just under 149 million people, will be the primary targets for the first rounds of vaccine but in no particular order. Only in rare situations of shortages, Schuchat noted, would certain sectors within that larger group be prioritized (bringing the total number of the core down to about 41 million).

But it’s unlikely that all—or possibly even most—of those in the recommended groups will get the vaccine, as less than 42 percent of those recommended to get the seasonal flu vaccine actually have in years past.

The vaccine supply may be more limited in the U.S. than other countries, however, as the U.S. Food and Drug Administration (FDA) has not licensed any vaccines that use adjuvants, which increase the effectiveness of the dose, thereby making smaller amounts of the actual antigen necessary.

Notably missing from the list was the 65-plus crowd, which is often hit hard by seasonal flu. But, as Schuchat explained, “The H1N1 virus has been sparing those people to a large extent.”

The announcement comes a day after a study was published online in The Lancet detailing the higher risk that pregnant women face from the flu. The study analyzed the 34 cases of pregnant women who were diagnosed with the flu in April and May of this year. Of those women, 11 of them were hospitalized and six died. These hospitalization and fatality rates were far higher than those for the average population.

Although pregnant women have many of the same initial H1N1 virus symptoms as the rest of the population, complications are much more likely, according to the study, which recommends that pregnant women be given Tamiflu before test results for the virus even come back. Many health care workers, however, were initially reluctant to dispense the antiviral because, as the study notes, “information about the safety and effectiveness of these anti-influenza drugs during pregnancy is scarce.” But the general sentiment is now that, “the benefits of treatment with these drugs are likely to outweigh potential risks to the fetus,” the paper concludes.

Image courtesy of iStockphoto/AndreasReh